Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the full behavioral burden. It discloses the topics covered (iPhone models, EID, receiving SMS on a Taiwan number) but not whether the tool returns a computed estimate, a static guide, or both, nor any constraints on the calculation. Minimal disclosure for a zero-annotation tool.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single sentence, front-loaded with a category tag that adds no selection value and a parenthetical enumerating covered topics. It is compact but the bracketed prefix and the topic list dilute rather than focus the signal.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Three parameters with no schema descriptions, no output schema, and no annotations — the description would need to carry parameter and behavioral detail to be complete, and it does not. An agent cannot know what the estimate is computed from or what the response contains.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 0% and the description never mentions the three parameters (days, usage level, hotspot_people). The words 流量估算 loosely imply a usage estimate, but no parameter meaning, units, enum semantics (light/normal/heavy), or hotspot behavior is explained anywhere. With zero schema coverage the description should have compensated and does not.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The core phrase 出國 eSIM 流量估算與設定說明 states a reasonably specific resource (overseas eSIM data) and two actions (usage estimation, setup guidance). However, it is prefixed with a generic category tag ［出國與國旅實用查詢］ and never distinguishes itself from travel siblings like trip__destination_info or trip__exchange_rates, leaving the agent to infer that this is the eSIM calculator.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

No statement of when to use this tool versus alternatives, no prerequisites, no trigger conditions. The only hint is the bracketed 'outbound travel' framing, which is implied usage at best. Among ~90 siblings, nothing routes the agent here specifically.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.